Preparation of sulphonate-containing core/shell latex particles via seeded emulsion copolymerization

In this study, P（St-MAA） seed latex particles were first prepared via soap-free emulsion polymerization of styrene （St） and methacrylic acid （MAA）, then the seed particles were allowed to swell with St at room temperature, and the P（St-MAA）/P（St- NaSS） core/shell latex particles were then synthesized via seeded emulsion copolymerization of St and sodium styrene sulphonate （NaSS） using AIBN as initiator in the presence of N,N^-methylenebisacrylamide （BAA, water-soluble crosslinker）. Results showed that the polymerization could be carried out smoothly when the ratio of BAA to total monomers was less than 3 mol%, the narrow dispersed P（St-MAA） seed particles with the diameter of 150 nm and the P（St-MAA）/P（St-NaSS） core/shell latexes with the particle size of about 200 nm were synthesized. When the 25/75 mole ratio of NaSS/（St ＋ MAA） and 2 tool% of BAA were used in the seeded emulsion polymerization, the resulted P（St-MAA）/P（St-NaSS） latex product showed a low weight loss after water extraction, and the NaSS unit content in the whole particle and in the shell reached 11.7 mol% and 34.6 mol%, resoectivelv.

Synthesis of crosslinked polystyrene particles by seeded batch polymerization with monomer absorption

A highly crosslinked, monodispersed polystyrene（PS） particle was prepared by a seeded batch dispersion polymerization with a monomer absorption method. Prior to polymerization, 1,9 lam monodispersed PS seed particles were treated under an optimum condition of monomer absorption. The effects of divinylbenzebe（DVB） concentration and polymerization temperature were examined for styrene（in PS seed）/styrene（in the second stage） mass ratio of 1：1 in the medium range of EtOH/water mass ratio of 100/0-80/20 and 2.3 μm uniform crosslinked PS particles containing 15%-20% （mass fraction） DVB were prepared at 60-70 ℃. The results show that monomer absorption before the second stage of polymerization is more effective to prepare highly crosslinked monodispersed PS particles.

SEED SEMICONTINUOUS EMULSION MULTI-COPOLYMERIZATION OF (METH) ACRYLATES WITH HIGH-SOLID CONTENT: EFFECT OF THE OPERATION CONDITIONS

The seeded semicontinuous emulsion multi-copolymerization of butyl acrylate (BA), 2-ethylhexyl acrylate (2EHA), methyl methacrylate (MMA), 2-hydroxyl propyl acrylate (HOPA) and acrylic acid (AA) was used to prepare the acrylic latexes with high-solid content. The effects of monomer emulsion feed rates (R(a)) and (R/E)(E) values, the ratio of emulsifier amount between the initial charge (R) and the addition monomer emulsion (E), on the polymerization reaction features, the viscosities, surface tensions,particle sizes and particle sizes distributions of latexes, T-g and the insoluble fractions of films, the 180 degrees peel strength, tack and holding power of pressure-sensitive adhesive (PSA) tapes, prepared from the latexes, were studied. Experimental study shows that the grafting and crosslinking fraction in the PSA tapes must be controlled within a suitable range to keep the balance of the 180 degrees peel strength, tack and holding power.

Morphology Control of Polymer Microspheres Containing Block Copolymers with Seed Polymerization

Microspheres based on binary polymer blend consisting of polystyrene (PSt), poly (methyl methacrylate) (PMMA), block copolymer comprising PSt and PMMA subunits, and ternary polymer blend consisting of PSt, PMMA, and block copolymer were fabricated by a solvent evaporation method, in which a polymer solution in dichloromethane was dispersed in water phase with the aid of a homogenizer to obtain an O/W emulsion followed by solvent evaporation with agitation to solidify the polymer. In the case of ternary blend, the effect of block copolymer content on the morphology of resulting spheres was investigated. Ternary blends afforded the bi-compartmental morphologies, the intermediate morphology between Janus and core-shell, which was confirmed by TEM observation. Seed polymerization of St or MMA was also carried out utilizing the resulting microspheres as seed particles in order to control the shape, and the surface morphology of particles. The particles with snowman-like morphology were obtained by seed polymerization of St using PSt/PMMA binary blend microspheres as seed particles. Surface roughness was controlled by the polymerization of MMA in the block copolymer seed, and that of St in the ternary blend seed.

Synthesis of Bowl-like Particles by Emulsion Polymerization and Release Behavior of Solvent from the Particles

Bowl-like poly (styrene-co-glycidyl methacrylate) was synthesized by swollen seeded emulsion polymerization. The polymerization was carried out in PS seed emulsion swollen by toluene, whereby the bowl-like particles formed at last. The shape was observed by SEM. These particles became ball-like when swollen by toluene, observed by optical microscope, and the release behavior of solvent from them was examined.

A method to refine crude cottonseed oil using non-toxic polyamine-based cationic polymers

The traditional method to refine crude cottonseed oil is time-consuming and expensive.This study evaluates the effectiveness of coagulation–flocculation–sedimentation process using quaternary polyamine-based polymers in refining crude cottonseed oil.Flocculated by four commercial polyamine-based cationic polymers(SL2700,SL3000,SL4500 and SL5000)with varied molecular weight(MW)and charge density(CD)and followed by coagulation with sodium hydroxide,crude cottonseed oil can be effectively purified.Free fatty acids,gossypol,pigments and trace elements are all effectively and sufficiently removed by the four polymers in a MW-and CDdependent manner.Our results suggest that the use of polyamine-based cationic polymers may offer an effective and feasible alternative to the traditional method for crude cottonseed oil refining.

SYNTHESIS OF BOWL-LIKE PARTICLES BY EMULSION POLYMERIZATION AND RELEASE BEHAVIOR OF SOLVENT FROM THE PARTICLES

Poly(styrene-glycidyl methacrylate) particles having bowl-shaped hollow structures were synthesized by swollen seed emulsion polymerization. The PS emulsion synthesized through soap-free emulsion polymerization was swollen by toluene, and then the mixture of second monomers was added under polymerization condition. So a thin shell of poly(styrene-glycidyl methacrylate) cross-linked by triethylene glycol diacrylate was formed around the swollen PS particle. The bowl-shaped particles were obtained after the collapsing of the thin shell when the toluene emanated from the particles, but the shapes were effected by the degrees of cross-linking. The shape of the particles was observed by SEM. The release behavior of solvent from the particles was examined by TG.

Effect of Polymerization Temperature on Cationic Emulsion Properties

The objective of this work was to analyze the effects of the polymerization temperature on the kinetic features(instantaneous and overall conversions)and colloidal characteristics[mean particle diameter,stabilities]in the semicontinuous seeded cationic emulsion polymerization of styrene and butyl acrylate.Azobis is obutyl amidine hydrochloride was used as an initiator.The surfactants wascetyl trimethyl ammonium chloride.The results showed that the final instant when the polymerization temperature of 85℃emulsion highest conversion rate,and the temperature of the emulsion particle size,centrifugal stability is the best,85℃emulsion in the emulsion anti-dilution and acid salt stability also showed excellent stability.

Synthesis of submicron-sized peanut-shaped poly(methyl methacrylate)/polystyrene particles by seeded soap-free emulsion polymerization

Submicron-sized peanut-shaped poly（methyl methacrylate）/polystyrene （PMMA/PS） particles were successfully synthesized by seeded soap-free emulsion polymerization of styrene on the spherical crosslinked PMMA seed particles. The obtained peanut- shaped particles showed a novel internal morphology： PS phase formed one domain which linked to the other domain having PMMA core encased by PS shell.

PREPARATION OF MICRON-SIZED NONSPHERICAL POLYSTYRENE/POLY(STYRENE-co-ETHYLENEGLYCOL DIMETHACRYLATE) PARTICLES BY SEEDED SOAP-FREE EMULSION POLYMERIZATION

Micron-sized nonspherical polymer particles having different morphologies were synthesized by seeded soap-free emulsion polymerization of styrene （St） and ethyleneglycol dimethacrylate （EGDMA, used as a crosslinker） on spherical, linear polystyrene （PS） seed particles. The morphology of the resulting PS/poly（St-co-EGDMA） particles was dependent on the crosslinker concentration and polymerization temperature.

The Doubly Thermo-responsive Triblock Copolymer Nanoparticles Prepared through Seeded RAFT Polymerization

The doubly thermo-responsive triblock copolymer nanoparticles of polystyrene-block-poly（N- isopropylacrylamide）-block-poly[N,N-（dimethylamino） ethyl methacrylate] （PS-b-PNIPAM-b-PDMAEMA） are successfully prepared through the seeded RAFT polymerization in situ by using the PS-b-PNIPAM-TTC diblock copolymer nanoparticles as the seed. The seeded RAFT polymerization undergoes a pseudo-first-order kinetics procedure, and the molecular weight increases with the monomer conversion linearly. The hydrodynamic diameter （Dh） of the triblock copolymer nanoparticles increases with the extension of the PDMAEMA block. In addition, the double thermo-response behavior of the PS-b-PNIPAM-b-PDMAEMA nanoparticles is detected by turbidity analysis, temperature-dependent 1H-NMR analysis, and DLS analysis. The seeded RAFT polymerization is believed as a valid method to prepare triblock copolymer nanoparticles containing two thermo-responsive blocks.

Poly(methyl methacrylate)/Poly(N-isopropylacrylamide) Core-Shell Particles Prepared by Seeded Precipitation Polymerization: Unusual Morphology and Thermo-sensitivity of Zeta Potential

Poly（methyl methacrylate）/poly（N-isopropylacrylamide） （PMMA/PNIPAM） core-shell particles were synthesized by seeded precipitation polymerization of N-isopropylacrylamide （NIPAM） in the presence of PMMA seed particles. The anionic potassium persulfate was used as initiator, and acrylic acid as functional comonomer. It was shown that the weight ratio of the PNIPAM shell to the PMMA core can be greatly increased through continuous addition of NIPAM monomer at a relatively slow rate. PMMA/PNIPAM particles with different shell thickness were obtained by varying the amount of charged NIPAM monomers. These particles exhibited unique nonspherical core-shell morphology. PMMA core was partially coated by dense hair-like or antler-like PNIPAM shell depending on the shell thickness. The measurement of these particles＇ zeta potential at different temperatures showed that the absolute value of zeta potential unusually decreased as the particle size decreased with temperature.

N⁃苯基马来酰亚胺共聚物的合成及对PVC树脂耐热改性效果研究

通过种子乳液聚合结合半连续加料方式,成功聚合出分子结构一致且与聚氯乙烯(PVC)树脂具有良好相容性的聚(N‐苯基马来酰亚胺‐苯乙烯‐丙烯腈)(PNSA)共聚物胶乳,将其与PVC树脂直接复合制备PNSA/PVC复合材料,并对PNAS耐热改性的效果进行评价。结果表明,PNSA纳米胶乳颗粒粒径在155.3~251.5 nm之间,粒径分布均一;PNSA共聚物分子组成呈无规结构,分子结构一致,差示扫描量热曲线呈现单一的玻璃化转变温度(T_(g)),且与PVC树脂具有极佳的相容性;PNSA含量由0升高至50%(质量比,下同)时,复合材料的T_(g)由84.8℃提高到107.2℃,提高了22.4℃,维卡软化温度由71.2℃提高到91.9℃,提高了20.7℃;除耐热性改善以外,复合材料的力学性能也有一定程度的提高,本文的研究有利于PVC应用领域的进一步拓展。

黏合剂与纤维组合对喷播基质材料抗剪性能及植物生长的影响

【目的】明确添加“黏合剂+植物纤维”对客土喷播初期基质抗剪性能和植物生长的影响,为工程实践提供参考。【方法】采用环刀法、直接剪切法和模拟坡面法,选择聚丙烯酰胺(PAM)和聚乙烯醇(PVA)2种黏合剂与棕榈纤维(PF)、椰丝纤维(CF)、剑麻纤维(SF)、木纤维(WF)4种植物纤维,探究黏合剂和纤维两两组合下喷播基质的孔隙度、抗剪性能及植被生长特征。【结果】1)PAM+SF组合孔隙度表现最优,其总孔隙度和毛管孔隙度显著高于CK(P<0.05),分别是CK的1.26倍和1.37倍;2)添加PAM能够提高纤维-土复合体的抗剪强度,PAM+CF和PAM+SF组合内摩擦角显著大于CK和其他处理组(P<0.05),分别是CK的1.71倍和1.88倍,PAM+PF组合内聚力显著高于CK(P<0.05),是CK的1.14倍。3)PVA+SF组合的植物生长状况最优,总生物量与根冠比显著大于CK(P<0.05)。【结论】添加PAM的组合能够提高喷播基质的抗剪性能;2种黏合剂相比,添加PAM的组合抗剪强度优于添加PVA的组合。并且喷播基质的抗剪性能变化由黏合剂和植物纤维共同影响。添加“黏合剂+植物纤维”,对植被生长恢复友好。

姜黄素-聚苯乙烯载药微球制备及其药物释放的研究

以苯乙烯为原料,分别采用种子溶胀法、悬浮法制备聚苯乙烯多孔微球,以聚苯乙烯多孔微球为载体,姜黄素为负载药物,制备出姜黄素-聚苯乙烯载药微球。考察微球质量、负载药物浓度、反应时间对微球载药率以及包封率的影响。结果表明,悬浮法、种子溶胀法制备的微球均有较好的载药功能,但种子溶胀法制备的多孔微球在载药和释药方面的效果更加显著。释放率试验分析,在10 h内累计缓释率仅达到18.2%,未出现突释的现象,该材料具有药物缓释的作用。

聚合物水泥防水涂料用苯丙乳液的研制及其各因素影响研究

通过预乳化半连续种子乳液聚合法自制了JS防水涂料专用苯丙乳液,并由此制备了聚合物水泥防水涂料。研究了乳化剂用量及其分配对苯丙乳液粒径及其吸水率的影响,同时通过尝试不同的方法降低乳液残留单体减少VOC排放。在自制苯丙乳液的基础上探究不同液粉比对聚合物水泥防水涂料拉伸性能的影响,通过添加一些不同的助剂来提升聚合物水泥防水涂料的综合性能。

种子乳液法PVC糊树脂聚合安全的影响因素及控制措施

对种子乳液法PVC糊树脂生产过程中影响聚合生产安全的因素进行了分析,并根据生产特点及生产工艺提出了提升反应安全性的措施。

苯乙烯微乳液种子聚合

通过观测苯乙烯微乳液种子聚合前后体系内聚合物粒子大小及其分布的变化发现，无论是γ射线还是ＫＰＳ引发，聚合过程中都没有新的聚合物粒子生成．尽管聚合前体系中存在单体溶胀的胶束，但在聚合过程中这些胶束主要充当单体仓库，自己成核聚合的几率很低．由于微乳液种子聚合体系内，单体量相对较低，聚合物粒子数目很大，其聚合动力学明显不同于常规乳液种子聚合．

种子溶胀悬浮聚合法制备分子印迹聚合物微球

以酪氨酸为印迹分子 ,甲基丙烯酸为功能单体 ,三羟甲基丙烷三甲基丙烯酸酯 (TRIM )为交联剂 ,采用种子溶胀悬浮聚合法在水溶液中制备了一系列分子印迹聚合物微球 (MIPMs)。利用扫描电镜 (SEM)对此微球的粒径大小、粒径分布、表面孔与孔径分布等进行了分析研究 ,探讨了影响其形貌的主要因素 ,并将所得微球用作色谱固定相研究了其分子选择吸附性能。研究表明 ,种子溶胀悬浮聚合法能够制得单分散性较好的、表面带有微孔的分子印迹聚合物微球 ,且该微球呈现出较好的特异吸附性能。

多孔聚合物微球的制备及其在化妆品中的应用进展

简要介绍了单分散多孔聚合物微球的应用,重点综述了多孔聚合物微球用作化妆品活性物载体时所起的控释和缓释作用;讨论了多孔聚合物微球的合成手段,包括悬浮聚合法、分散聚合法和种子溶胀法,种子溶胀法中的动态溶胀法和二步溶胀法更易得到粒径均一的多孔聚合物微球;同时介绍了其成孔机理和性能表征;最后提出了多孔聚合物合成以及在化妆品应用中目前存在的问题、发展方向和应用前景。